Radioreceiver



Feb. 11, 1930.

B. WASHINGTON RADIORECEIVER Filed Feb. 9. 1927 5 SheetQ-Sheet 1 Feh ll,1930. B. WASHINGTON RADIOREGE I VER Filed Feb. 9. 1927 6 Sheets-Sheet 2Jwuwntoz Feb. 11, 1930. B. WASHINGTON RADIORECEI VER Filed Feb. 9. 19273 Sheets-Sheet 5 06k w w Sums Svwwntoi Patented Feb. 11,1930

UNITED STATES PATENT OFFICE BOWDEN WASHINGTON, OF NEW YORK, N. Y.,ASSIGNOR TO REMOTROLE CORPORATION v A CORPORATION OF NEW YORKBADIOBECEIVER Application filed February 9, 1927. Serial No. 166,992.

One object of my invention is to produce a remote controlled radioreceiver in which the wave length to which it best responds and theVolume of the output may be controlled from a distant point.

Another object is to produce an attachment for existing receivers toattain the above mentioned results. The modern broadcast re ceiver hassufiicient undistorted output to be clearly heard anywhere on a singlefloor of theaverage dwelling house or anywhere in the average apartment.A receiver of this type is too large and heavy tobe conveniently movablefrom room to room. Yet, it is most annoying for the listener to have toremain by the receiver in order to effect a change of program, whendesired, or to be continually gettingup and going to the receiver tochange the program or the volume.

One object is to provide a method of reception and control which willmake it possible for'the operator toenjoy such program as he desireswith a minimum effort.

By means of my invention, which will not add prohibitively to the costof the receiver,

.both these adjustments may be effected from a distance. The control box'may be made small and light enough to be readily portable. Its powermay be supplied from the alternating current house mains and it may beprovided with a cord and plug so that it may be attached to any existinglamp socket, base plug or other outlet.

Referring to the drawings, Fig. 1 is a schematic wiring diagram, of areceiver embodying one form of my invention with a. schematic wiringdiagram of its control station.

Fig. 2 is a diagrammatic drawing of another form of apparatus of myinvention.

. Fig. 2 is a diagram showing one arrangement of circuits for theoscillating high frequency detector of Fig. 2."

Fig. 3 is a partly schematic and partly diagrammatic drawing of a formof my invention which may be readily associated or used with the usualtuned radio frequency receiver or other sufficiently sensitive sets.

In Fig. 1 the antenna 5 is connected to the ground 6 through the primary7 of the band amplifying transformer 7 consisting of the coupledinductances 7 and 8. The secondary 8 of this transformer is connected tothe grid 9 and the filament 10 of the tube 11. The plate 12 is connectedthrough the primary 13 to the anode voltage supply line 14. The primary13 and the secondary 15 form a second band amplifying transformer 13forming the input circuit of the tube 16.

The out-put circuit of the tube 16 is coupled by means of the bandamplifying transformer 17 to the detector tube 18 wh1ch may be providedwith the grid leak 19 and the grid condenser 20. The outut of the tube18 includes an intermediate requency resonant circuit frequently calleda filter circuit consisting of a condenser 21 and the inductance 22. Theinductance 22 forms a primary of the intermediate frequency transformer23 having a secondary 24 included in the grid circuit of theintermediate frequency amplifying tube 25. Two additional intermediatefrequency transformers 26 and 28 may be provided with their respectivetubes 27 and 29. The out-put of the tube 29 is coupled by intermediatefrequency transformer 30 to the in-put circuit of the detector tube 31.This circuit consistsof the secondary inductance 32, the grid leak 33and the grid condenser 34. v

} Terminals 35 and 36 are provided so that the out-put of the detector31 may be introduced into any suitable audio frequency amplifier (notshown).

The control station 40 may be provided with power in any suitable mannerfor instance at its in-put with a cord and plug 41 for providingalternating current power to the primary 42 of the transformer 43, theamount of power being regulated by the rheostat 44 which serves as again control forthe receiver. One secondary 45 of this transformer mayhave its terminations connected to the plates 46 and 47 of the full waverectifier 48. The filament 49 of this rectifier may be heated from thewinding 50, and the filament 51 of the oscillator tube 52 may be heatedfrom winding 50.

The central point of the secondary 50 may be led through the smoothinginductance 54 and the feed back coil 55 to the anode 56 of theoscillator tube 52.

The filtering condensers 57 and 58 may be provided. The grid-circuit ofthe oscillator may consist of the inductance 59, the radiating loop 60and the variable condenser 61. The grid return of the oscillator may bebrought to the central point of resistance 62 which is also connected toa central tap of the winding -15.

r The tubes 11 and 16 with their associated circuits form a bandamplifier which will am plify with substantial uniformity over a desiredband of frequencies, such as, the prescut broadcast band (550 to 1500kilocycles). A frequency such as, 50 kilocyclesmay be chosen as aresonant frequency of the filter transformer 23 and as the peakfrequency of the following intermediate frequency amplifier system. Theband amplifier is provided to make up for the gain lost by not using aresonant in-put circuit.

In operation, the remote control station 40 is set in operation and thecondenser 61 is adjusted until the energy radiated from the loop intothe in-put of the receiver differs in frequency from the wave that it isdesired to receive by the frequency chosen for the resonant frequency ofthe intermediate frequency amplifier system, thus producing a beatfrequency in the output of the tube 18 which is resonant to theintermediate frequency amplifier.

In a receiver such as just described the pick up system or antennacircuit 5, 7, 6 is more sensitive to the transmitted signal from theoscillation output 60 than the band amplifier coils which would normallybe neutral with respect to external fields or otherwise efi'ectivelyshielded.

The strength of the out-put of the receiver may be variedby varying thestrength of the oscillations radiated from the loop 60 by various meanssuch as the rheostat 44. The loop 60 may preferably be in a horizontalplane, thus polarizing its radiation in a manner least liable to affectother neighboring receivers.

In Fig. 2 the band amplifier covering the desired receiving frequencyband is indicated at 65, the first detector at 66, the intermediatefrequency filter amplifier at 67, the second detector at 68, an audiofrequency amplifier at 69 and an out-put conversion device such as aloud speaker at 70. 71 indicates an oscillating detector whose frequencymay, be adjusted or set by the manual control 72 at any desired value.In the in-put of this oscillating detector is connected the loop 73, andits out-put is introduced along with the received signal into the in-putof the first detector 66.

Fig. 2 shows one method of connecting the component parts of the circuitof the oscillating detector 71.

The vacuum tube 71 has in its anode circuit the feed back inductance 78,which may be coupled to the coil 78' included in the grid circuit, thedelivery coil 17, which may be coupled with the secondary of transformer'17 (Fig. 1) of the receiver proper ahead of the first detector 66 (Fig.2), and the by-pass condenser 79. The usual direct current anode sourceis indicated by the letters B and B. The grid circuit contains the gridleak 90, the grid condenser 91, to ensure the production of thenecessary difference frequency, the feed-back coupling inductance 78',the condenser 72' and the pick-up device or loop 73.

t The control box 74 or oscillator is constructed in any suitable mannerand contains any suitable oscillator system and power source and isprovided with the frequency adjustment 75 and amplitude adjustment 76.Its out-put circuit includes the loop 77. This oscillator 7 4 and thefrequency control circuit of the oscillating detector 71 may bepreferably adjustable over a band of frequencies considerably higherthan those to be received.

For purposes of explanation, let it be assumed that the desired incomingwave has a frequency of 550 kilocycles and that the intermediatefrequency filter amplifier 67 has a chosen frequency of 50 kilocycles.Let us also assume that the oscillating detector 71 has been adjusted tooscillate at a frequency of 5000 kilocycles. Then, if we adjust thecontrol station 74 to emit awave of a fre quency of 5500 kilocycles,this wave will be received and heterodyned by the oscillating detector71 whose out-put will then have a frequency of 500 kilocycles. This isthe correct frequency to heterodyne the incoming 550 kilocycles in thefirst detector 66 and will produce an output frequency of 50 kilocycleswhich is correct for the intermediate frequency amplifier 67.

With this embodiment of my invention, several of these receivers, withtheir associated control stations, may be used in a sin gle localitywithout interference between them, as by means of the adjustment 72 ofthe oscillating detector 71 any one of a number of bands may be chosenin which the control wave from the control box 74 may be confined,without overlapping other control bands.

The oscillator 74 and its responsive detector 71 may be designed fornormal operation within any desired frequency limits or the oscillator74 and the oscillating detector 71 may be provided with a multi;pointswitch (not shown) which may vary the inductance or the capacity oftheir respective oscillating circuits by several steps, such steps beinglarge enough so that the continuously variable control75, of theoscillator will not permit of an overlap between the frequency bandsrepresented by these steps. These steps may be designated by letters ornumerals, or in any other suitable manner, so that if several of thesereceivers were installed close together, the control waves need neveroverlap. Interference between the controlling means of the variousreceivers will thus be avoided. The out-put of the oscillating detector71 may beintroduced into the grid circuit of the first tube (not shown)of the band amplifier 65, thus greatly reducing the power required bythe high frequency oscillator 74;. The oscillator maythen be of such lowpower as to preclude the possibility of interference with others.

Fig. 3 shows a method of applying my invention to ordinary tuned radiofrequency types of receivers. In this case a differential frequencyconverter unit 80 is provided which is inserted between the antennasystem 81 and the input of a receiver 82. In case the input of thereceiver 82 includes a series] condenser this condenser should beshortcircuited or a radio frequency choke placed across the input terminalsto allow for-the direct current anode flow. The remote control boxoscillator 83 such as heretofore described and shown in Fig. 1 isprovided. The converter 80 as illustrated has a two-stage band amplifierand detector similar to that associatec with tubes 11, 16 and 18 inFig. 1. e

In operation the tuning controls 84, 85 and 86 of the receiver 82 areadjusted until their associated circuits are resonant to the samefrequency, which frequency may preferably be the lowest at which thereceiver will operate. For purposes of explanation, let us. assume thatthis. frequency be 500 kilocycles and that the frequency band which itis de-.

sired to receive be from 1500 to 550 kilocycles. Then, if theoscillator,83 has a range of 2000 to 1050 kilocycles. 500 kilocyclebeats can be produced at will in which case the radio frequency part ofthe receiver 82 will function as an intermediate frequencv amplifier.The detector of this set 82-will now function as a second detector forits audio frequency amplifier. v

Owing to the fact that there is no resonant selectivity at the incomingsignal frequency and only the arithmetic selectivity remains, it may befound advisable to employ more than a single stage filter in theintermediate frequency circuits.

It is also advisable to choose such a resonant peak frequency for theintermediate frequency filter amplifier that beats-between any twotransmitting stations will not be in resonance with this amplifier. Forinstance, with the present interval between broadcast stations of 10kilocycles a frequency of 40 or kilocycles can be produced by stations 3or 4 intervals apart but if 45 or kilocycles is chosen this will notoccur. To ensure that no difficulties of this sort occur a several cellband-pass filter may be incorporated in the filter'amplifier which mayhave its cut-offs at for example 51 and 59 kilocycles. To obtain 1 besttone quality I prefer to adjust the portable oscillator 74: to afrequency which will place the carrier current in the band-pass filter.close to one of its cut-offs or limits thus allowing the full frequencyrange of the filter for one side band. By this method of tuning it isalso possible to separate two stations which might differ in frequencyequally but above and below the output frequency of the oscillatingdetector if the intermediate carrier current frequency were midwaybetween the limits of the band-pass filter employed.

I do not Wish to limit myself to the detec-. tion methods, type ofoscillating circuits,

number of stages, type of oscillator power.

supply or type of gain control except in so far as may be set forth inthe appended claims and re uired by the prior art.

The particu ar combinations illustrated-in 'Figs. 1 and 3 are claimedspecifically in my application #217 ,7 07 filed September 6, 1927.

I claim:

*1. A remote controlled radio receiver, having a band pass amplifier, anoscillating detector connected with said amplifier and havlng a normallyfixed frequency, said frequency being well outside of the responsefrequency of said band pass amplifier, pick-upmeans connected with saidoscillating detector, an independently portable oscillator having outputmeans and of such variable frequency as will coact with said detectorand pick-up means and produce beats with the signals'received throughsaid band pass amplifier, a detector connected with the output ofsaidamplifier, a filter-amplifier resonant to the output of said latterdetector and another detector connected with the output of saidfilter-amplifier, .said portable oscillator having such characteristicswith respect to the characteristics of the remainder of the apparatusthat it will coact therewith within the range of an ordinary apartment.

2. A remote controlled radio receiver whose response frequency andresponse amplitude may be controlled from a distance having aband passamplifier, an oscillating detector associated with said amplifier andhaving a normally fixed frequency, said frequency being well outside ofthe response frequency of said band pass amplifier, pick-up meansassociated with said oscillating detector, a separate oscillator of suchvariable lator being movable with respect to the remainder of theapparatus and having radiating means coupled to its output means,adapted to co-actwith said pick-up means within the area of an ordinaryapartment, and means for varying the power of the output of the separateoscillator.

3. A remote controlled radio receiver com prising an input systemincluding non-selective means for collecting and amplifying broadcastsignals within a broadcast range of. frequencies, separate, remote andportable meansyfor producing control oscillations of variousfrequencies, means for varying the power of frequency of said controloscillations, means for selectively radiating control oscillations of apredetermined frequency,

means connected with the input system for collecting the selectedcontrol oscillations to produce the desired intermediate frequency fromthe incoming signals, and means for reroducing the signals from saidintermediate requency.

4. In a radio receiver, a band amplifier having signal collecting means,a detector, oscillating and detecting means of normally fixed frequencyhigher than the frequency covered by said band amplifier and associatedwith said amplifier and having input means, a separately movable sourceof radiant oscillating energy having frequency control and power controland having means for transmitting to the said input means ofsaidoscillating and detecting means and producing a lower frequency in theout-put of said oscillating and detecting means, means for combiningsaid out-put frequency with incoming signal frequency so as to produce astill lower frequency means for detecting said lower frequency, andaudio frequency amplifier means associated therewith.

In a radio receiver, a band'amplifier, a detector, oscillating anddetecting means of normally fixed frequency higher than the frequencycovered bysaid band amplifier associated with said amplifier and havingpickup means, an independently portable source of radiant oscillatingenergy having frequency control and power control and having means fortransmitting to said oscillating and detecting means and coacting withsaid pickup means to produce a lower frequency in the out-put of saidoscillating and detecting means, means for combining said out-putfrequency with incoming signal frequency so as to produce a still lowerfrequency and means for detecting said lower frequency.

6. A household receiving set comprising three units namely a receivingunit, a port- "able control unit and a reproducing unit, all

adapted to be located in a single apartment, said control unit beingentirely separate from the other units and adapted to be moved in theapartment from place to place with respect to the other units, saidreceiving unit ineluding a band amplifier having signal energycollecting means and adapted to receive and amplify all signals within abroad band of frequencies, said control unit includ-, ing 'highfrequency oscillation apparatus, power supply, amplitude control meansand radiating means and said reproducing unit including means foramplification at a fixed super-audible frequency, detecting means andaudio frequency sound converting means.

7. A radio receiving set adaptable for being controlled from a distancecomprising local receiving apparatus and an unattached controloscillator having output means, said receiving apparatus consisting ofan untuned radio frequency amplifier, a detector and a fixed local highfrequency oscillator coupled with said amplifier and detector and havinglocal pickup means, an intermediate frequency band-pass filteramplifier, said local oscillator pick-up means being adapted forinteracting with the output means of said unattached control oscillatorto produce at said detector when receiving signals a resultant frequencyequal numerically to a re.- sponse frequency within the band of saidintermediate frequeny amplifier.

8. A radio receiver adaptable for being controlled by locally generatedcontinuous waves, said receiver having a separately portable variablecontrol oscillator with output means, an untuned radio frequencyamplifier, a first detector associated with the out-put of said untunedamplifier, an intermediate frequency band-pass filter amplifierassociated with the out-put of said first detector, a local oscillatorof fixed frequency associated with said untuned amplifier and havingseparate pick-up means, a second detector connected to the out-put ofsaid filter amplifier, means con nected to said variable controloscillator to transmit continuous waves of variable frequency andintensity, said continuous waves being collected by'said pick-up meansand adapted to inter-act with said local oscillator and to roduce inconjunction witlrthe received signals a frequency in the out-put of thefirst detector equal numerically to a response frequency of theintermediate frequency filter amplifier and a second detector associatedwith the out-put of said filter amplifier, said second detector beingadapted to produce audio frequency currents.

9. In a remote controlled radio receiver comprising, means forcollecting signals of various frequencies within a predetermined band offre uencies, means for producing oscillations o fixed frequency outsidesaid band, remoteadjustablc means for producing control oscillations ofsuch frequency that when mixed with said fixed frequency oscillations aresultant frequency will be produced of a frequency differing from thefrequenc of the desired signal by a prede- V termin frequency, means formixing the fixed frequency oscillations with the control frequencyoscillations to produce oscillations differing from the frequency of thedesired signal by a definite final frequency, means .for detecting theoutput of the collecting means and the output of the mixing means andproducing oscillations of said final frequency, and means for amplifyingand detecting said final frequency.

10. In a remote controlled radio receiver comprising, means forcollecting and am lifying signals of various frequencies wit in apredetermined band of fre uencies, means for producing oscillations ofxedfrequency, remote adjustable means for producing con troloscillations of such frequency that when mixed with said fixed frequencyoscillations a resultant frequency will be produced of a frequencydiffering from the frequency of the desired signal by a predeterminedfrequency, means for mixing the fixed frequency oscillations with thecontrol frequency oscillations to produce escillations differing fromthe frequency of the desired signal by a definite final frequency, meansfor detecting the output of the collecting means and the output of themixing means and producing oscillations of said final frequency andselective means for amplifying and detecting said finalfrequency and oneof its side bands.

11. The. method of selective radio reception controlled from a distancewhich comprises collecting all signals within a predetermined band offrequencies covering a plurality of signal channels, producing controloscillations at a distance havin uencies outside the said band of coected requencies, mixing said control oscillations with oscillations ofa fixed frequency differamount other than the frequency of the desiredsignal, compoundin the result of said mixture with the collecte signals,detecting the results of said compounding and selecting an amplifyingfrom the detected result control oscillations by an 13. The method ofselective radio recepquency from the freqiueiicy of the desired signal,producing sa1 ering frequency by mixing a fixed frequency with aremotely generated adjustable frequency, and amplifying and detectingsaid lower frequency.

fre- I I a predetermined band of frequencies differ- I ing from allother received and frequencies.

' 12. The method of selective radio reception controlled from a distancewhich comprises collecting all signals within a predetermined band offrequencies covering alurality of signal channels, amplifying andetecting said signals, producing high frequency oscillations of acontrolled frequency,

mixing said controlled frequency with a fixed frequency and producing afrequenc having a predetermined difference from t e frequency of thesignal desired to be indicated,

mixing the desired signal with said frequen cy having the predetermineddifference and producing a frequency numerically equal to saiddifference and amplifying and redetecting the latter frequency.

produced fre uencies BOWDEN WASHINGTON.

